Advances in the Construction of Nitrogenous 5:6 Fused Heterocycles: Biologically Active Pyrazolo[3,4‐b] Pyridines

Pyrazolopyridines are bicyclic frameworks in which a pyrazole ring is fused to a pyridine ring. Both pyridine‐ and pyrazole‐based scaffolds are individually well recognized for their pharmaceutical relevance, and merging the two into a single molecular framework has produced pyrazolopyridines with a broad range of biomedical applications, biological properties, and notable photophysical behavior. Given the continued interest in this class of compounds, the present review offers a comprehensive account of the synthetic strategies reported over the last decade (2015–2025) for building pyrazolo[3,4‐ b ]pyridines, covering routes that start from pyrazole precursors, routes that start from pyridine precursors, and the rearrangement of pyrazolopyrimidines into pyrazolopyridines. The wide spectrum of biological activities associated with the pyrazolo[3,4‐ b ]pyridine core is also summarized.